Incidental Adnexal Lesions: CT Diagnosis and Interreader Agreement

Area of Science:

• Radiology
• Oncology
• Gynecologic Imaging

Background:

• The diagnostic accuracy of CT for incidental adnexal lesions is not well-established.
• Effective management relies on accurate diagnosis, yet evidence for CT-based diagnosis of most adnexal lesion types is limited.

Purpose of the Study:

• To assess the interreader agreement and diagnostic accuracy of CT for incidentally discovered adnexal lesions.
• To evaluate the performance of radiologists in diagnosing various adnexal lesion types using CT.

Main Methods:

• A multi-institutional, multireader retrospective study involving 75 patients with diverse adnexal lesions.
• Nine expert readers independently reviewed CT images, classifying lesions based on the American College of Radiology white paper.
• Statistical analysis included a 2x2 factorial random-effects model for accuracy and Gwet AC1 for interreader agreement.

Main Results:

• Highest accuracy and agreement were observed for dermoids (99%, 0.97), malignant ovarian lesions with metastases (94%, 0.90), and simple cysts (86%, 0.64).
• Accuracy for other lesion types was below 72%, with fair to moderate agreement.
• Malignant lesions were diagnosed more accurately (82%) than benign lesions (52%). A significant number of malignant lesions without metastases were misdiagnosed as benign (28%).

Conclusions:

• CT demonstrates high accuracy and interreader agreement for diagnosing dermoids, malignant ovarian lesions with metastases, and simple cysts.
• Diagnosing other adnexal lesions using CT remains challenging, with a notable tendency to misclassify malignant lesions as benign.
• Further research and improved CT interpretation guidelines are needed for challenging adnexal lesions.